Is obtained with production manner and this manner of the diatomaceous earth filter medium which the chestnut strike val stone the temporary quenching which is superior in the quite water permeability which is not included is done the filter medium

摘要

PURPOSE: To provide a production method for a highly permeable calcined diatomaceous filtration agent free from cristobalite, and the filtration agent obtained by this method. CONSTITUTION: In this production method for a diatomaceous filtration agent having a cristobalite content of =1% and a 50 μm screen remain rate of =5% by rapid calcination of diatomite, the diatomite is injected into a high temperature gaseous stream, maintaining the diatomite at about 1250 to 850 deg.C for a period of time of several tens of milliseconds to several seconds. By calcinating the diatomite in a fluidized refractory ball rings in a high temperature spiral gaseous stream, the calcination and aggregation of the diatomite can be controlled to maintain silica in a non-crystal structure.